package com.clouddms.controller;

import com.clouddms.service.transfer.FileTransferService;
import com.clouddms.service.transfer.ChunkUploadManager;
import com.clouddms.service.transfer.UploadProgress;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.HashMap;
import java.util.Map;

/**
 * 文件控制器
 * 处理文件上传、下载等网络传输请求
 *
 * @author Cloud-DMS Team
 * @version 1.0.0
 */
@Slf4j
@RestController
@RequestMapping("/api/transfer")
public class FileController {

    @Autowired
    private FileTransferService fileTransferService;

    @Autowired
    private ChunkUploadManager chunkUploadManager;

    /**
     * 智能文件上传接口（自动选择上传策略）
     *
     * @param file 上传的文件
     * @param userId 用户ID (临时参数，实际应从认证信息获取)
     * @return 上传结果
     */
    @PostMapping("/upload/smart")
    public ResponseEntity<Map<String, Object>> smartUploadFile(
            @RequestParam("file") MultipartFile file,
            @RequestParam(value = "userId", defaultValue = "1") Long userId) {

        log.info("收到智能文件上传请求: 文件名={}, 大小={} bytes, 用户ID={}",
                file.getOriginalFilename(), file.getSize(), userId);

        Map<String, Object> response = new HashMap<>();

        try {
            // 调用智能上传服务
            FileTransferService.UploadResult result = fileTransferService.smartUploadFile(file, userId);

            if (result.isSuccess()) {
                response.put("success", true);
                response.put("message", result.getMessage());
                response.put("data", createFileInfo(result));
                response.put("uploadStrategy", chunkUploadManager.shouldUseChunkedUpload(file.getSize()) ? "chunked" : "direct");

                log.info("智能文件上传成功: {}", result.getStoredName());
                return ResponseEntity.ok(response);

            } else {
                response.put("success", false);
                response.put("message", result.getMessage());

                log.warn("智能文件上传失败: {}", result.getMessage());
                return ResponseEntity.badRequest().body(response);
            }

        } catch (Exception e) {
            log.error("智能文件上传异常: {}", e.getMessage(), e);

            response.put("success", false);
            response.put("message", "系统异常: " + e.getMessage());
            return ResponseEntity.internalServerError().body(response);
        }
    }

    /**
     * 传统文件上传接口（兼容性保留）
     *
     * @param file 上传的文件
     * @param userId 用户ID (临时参数，实际应从认证信息获取)
     * @return 上传结果
     */
    @PostMapping("/upload")
    public ResponseEntity<Map<String, Object>> uploadFile(
            @RequestParam("file") MultipartFile file,
            @RequestParam(value = "userId", defaultValue = "1") Long userId) {

        log.info("收到传统文件上传请求: 文件名={}, 大小={} bytes, 用户ID={}",
                file.getOriginalFilename(), file.getSize(), userId);

        Map<String, Object> response = new HashMap<>();

        try {
            // 调用传统上传服务
            FileTransferService.UploadResult result = fileTransferService.uploadFile(file, userId);

            if (result.isSuccess()) {
                response.put("success", true);
                response.put("message", result.getMessage());
                response.put("data", createFileInfo(result));

                log.info("传统文件上传成功: {}", result.getStoredName());
                return ResponseEntity.ok(response);

            } else {
                response.put("success", false);
                response.put("message", result.getMessage());

                log.warn("传统文件上传失败: {}", result.getMessage());
                return ResponseEntity.badRequest().body(response);
            }

        } catch (Exception e) {
            log.error("传统文件上传异常: {}", e.getMessage(), e);

            response.put("success", false);
            response.put("message", "系统异常: " + e.getMessage());
            return ResponseEntity.internalServerError().body(response);
        }
    }

    /**
     * 文件下载接口
     *
     * @param fileId 文件ID (实际应查询数据库获取文件信息)
     * @param request HTTP请求
     * @param response HTTP响应
     */
    @GetMapping("/download/{fileId}")
    public void downloadFile(@PathVariable String fileId,
                             HttpServletRequest request,
                             HttpServletResponse response) {

        log.info("收到文件下载请求: fileId={}", fileId);

        try {
            // TODO: 实际应该从数据库查询文件信息
            // 这里为了演示，使用模拟数据
            String filePath = "uploads/users/user_1/" + fileId;
            String fileName = "download_" + fileId;
            boolean encrypted = false; // 实际应从数据库获取

            boolean success = fileTransferService.downloadFile(filePath, fileName, encrypted, request, response);

            if (!success) {
                log.warn("文件下载失败: {}", fileId);
                if (!response.isCommitted()) {
                    response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "文件下载失败");
                }
            } else {
                log.info("文件下载成功: {}", fileId);
            }

        } catch (Exception e) {
            log.error("文件下载异常: {}", e.getMessage(), e);
            try {
                if (!response.isCommitted()) {
                    response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, "系统异常");
                }
            } catch (Exception ex) {
                log.error("响应异常处理失败: {}", ex.getMessage());
            }
        }
    }

    /**
     * 获取上传进度 (分块上传支持)
     *
     * @param uploadId 上传ID
     * @return 上传进度信息
     */
    @GetMapping("/upload/progress/{uploadId}")
    public ResponseEntity<Map<String, Object>> getUploadProgress(@PathVariable String uploadId) {
        log.info("查询上传进度: uploadId={}", uploadId);

        Map<String, Object> response = new HashMap<>();

        try {
            UploadProgress progress = chunkUploadManager.getUploadProgress(uploadId);
            
            if (progress != null) {
                response.put("success", true);
                response.put("uploadId", progress.getUploadId());
                response.put("progress", progress.getProgressPercentage());
                response.put("uploadedBytes", progress.getUploadedBytes());
                response.put("totalBytes", progress.getTotalBytes());
                response.put("completedChunks", progress.getCompletedChunks());
                response.put("totalChunks", progress.getTotalChunks());
                response.put("status", progress.getStatus().name().toLowerCase());
                response.put("statusDisplay", progress.getStatus().getDisplayName());
                response.put("formattedProgress", progress.getFormattedProgress());
                response.put("isCompleted", progress.isCompleted());
                response.put("isActive", progress.isActive());
                
                return ResponseEntity.ok(response);
            } else {
                response.put("success", false);
                response.put("message", "上传会话不存在");
                return ResponseEntity.notFound().build();
            }

        } catch (Exception e) {
            log.error("查询上传进度异常: uploadId={}, error={}", uploadId, e.getMessage(), e);
            
            response.put("success", false);
            response.put("message", "查询进度失败: " + e.getMessage());
            return ResponseEntity.internalServerError().body(response);
        }
    }

    /**
     * 暂停上传
     *
     * @param uploadId 上传ID
     * @return 操作结果
     */
    @PostMapping("/upload/pause/{uploadId}")
    public ResponseEntity<Map<String, Object>> pauseUpload(@PathVariable String uploadId) {
        log.info("暂停上传: uploadId={}", uploadId);

        Map<String, Object> response = new HashMap<>();

        // TODO: 实现暂停上传逻辑
        response.put("success", true);
        response.put("message", "上传已暂停");
        response.put("uploadId", uploadId);

        return ResponseEntity.ok(response);
    }

    /**
     * 恢复上传
     *
     * @param uploadId 上传ID
     * @return 操作结果
     */
    @PostMapping("/upload/resume/{uploadId}")
    public ResponseEntity<Map<String, Object>> resumeUpload(@PathVariable String uploadId) {
        log.info("恢复上传: uploadId={}", uploadId);

        Map<String, Object> response = new HashMap<>();

        // TODO: 实现恢复上传逻辑
        response.put("success", true);
        response.put("message", "上传已恢复");
        response.put("uploadId", uploadId);

        return ResponseEntity.ok(response);
    }

    /**
     * 取消上传
     *
     * @param uploadId 上传ID
     * @return 操作结果
     */
    @DeleteMapping("/upload/{uploadId}")
    public ResponseEntity<Map<String, Object>> cancelUpload(@PathVariable String uploadId) {
        log.info("取消上传: uploadId={}", uploadId);

        Map<String, Object> response = new HashMap<>();

        // TODO: 实现取消上传逻辑，清理临时文件
        response.put("success", true);
        response.put("message", "上传已取消");
        response.put("uploadId", uploadId);

        return ResponseEntity.ok(response);
    }

    /**
     * 获取系统存储信息
     *
     * @return 存储信息
     */
    @GetMapping("/storage/info")
    public ResponseEntity<Map<String, Object>> getStorageInfo() {
        Map<String, Object> response = new HashMap<>();

        // TODO: 实现真实的存储信息统计
        Map<String, Object> storageInfo = new HashMap<>();
        storageInfo.put("totalSpace", 1024L * 1024 * 1024 * 100); // 100GB
        storageInfo.put("usedSpace", 1024L * 1024 * 1024 * 25);   // 25GB
        storageInfo.put("freeSpace", 1024L * 1024 * 1024 * 75);   // 75GB
        storageInfo.put("fileCount", 1250);
        storageInfo.put("encryptedFileCount", 520);

        response.put("success", true);
        response.put("data", storageInfo);

        return ResponseEntity.ok(response);
    }

    /**
     * 文件验证接口 (MD5校验)
     *
     * @param fileId 文件ID
     * @param expectedMd5 期望的MD5值
     * @return 验证结果
     */
    @PostMapping("/verify/{fileId}")
    public ResponseEntity<Map<String, Object>> verifyFile(
            @PathVariable String fileId,
            @RequestParam String expectedMd5) {

        log.info("文件完整性验证: fileId={}, expectedMd5={}", fileId, expectedMd5);

        Map<String, Object> response = new HashMap<>();

        try {
            // TODO: 从数据库获取文件路径
            String filePath = "uploads/users/user_1/" + fileId;

            // 使用加密服务验证文件完整性
            // boolean isValid = encryptionService.verifyFileIntegrity(filePath, expectedMd5);
            boolean isValid = true; // 临时模拟

            response.put("success", true);
            response.put("fileId", fileId);
            response.put("valid", isValid);
            response.put("message", isValid ? "文件完整性验证通过" : "文件完整性验证失败");

            return ResponseEntity.ok(response);

        } catch (Exception e) {
            log.error("文件验证异常: {}", e.getMessage(), e);

            response.put("success", false);
            response.put("message", "验证异常: " + e.getMessage());
            return ResponseEntity.internalServerError().body(response);
        }
    }

    /**
     * 创建文件信息对象
     */
    private Map<String, Object> createFileInfo(FileTransferService.UploadResult result) {
        Map<String, Object> fileInfo = new HashMap<>();
        fileInfo.put("originalName", result.getOriginalName());
        fileInfo.put("storedName", result.getStoredName());
        fileInfo.put("filePath", result.getFilePath());
        fileInfo.put("fileSize", result.getFileSize());
        fileInfo.put("contentType", result.getContentType());
        fileInfo.put("fileHash", result.getFileHash());
        fileInfo.put("encrypted", result.isEncrypted());
        fileInfo.put("uploadTime", System.currentTimeMillis());

        return fileInfo;
    }
}